Electrical switch actuating element

ABSTRACT

An actuating element for an electric switch, especially for a steering wheel switch in a motor vehicle, impinges upon at least one switching contact and is pivotally mounted on a housing of said switch. A firm hinge is provided as a bearing, connecting the actuating element to a latched wall. The wall runs parallel to the wall of the housing or replaces the wall of the housing.

TECHNICAL FIELD

The invention generally relates to electrical switches and moreparticularly related to an actuating element for an electrical switch.

BACKGROUND OF THE INVENTION

In general, in order to create a pivotable support for an actuatingelement of an electrical switch, support-axis stubs are formedperpendicularly to its direction of rotation, these stubs beingopposably arranged on the switch and being inserted in correspondinghousing recesses. However, the support-axis stubs are relatively proneto break, for which reason a reject can be generated if the actuatingelement is improperly mounted in the housing. If several such actuatingelements are to be housed in a common housing, a corresponding number ofsupport sites must be realized, at a significant manufacturing expense.

The direct connection of an actuating element to a housing via theintermediary of a film hinge is difficult in that the material for thehousing must have different material properties from the materialsuitable for a strip of film. This problem cannot be solved bymanufacture in a two-component injection molding process, since thedifferent materials no longer combine sufficiently homogeneously in thisprocess.

An actuating element for an electrical switch pivotably supported on apartition via a film hinge is known from U.S. Pat. No. 4,689,455 A. Thepartition is connected in a latching manner to a housing of the switch,and is aligned parallel to a housing wall. The actuating element and thepartition are set into a recess of the housing.

Moreover, JP 06 290680 A (Patent Abstracts of Japan, Vol. 1995, No. 1,Feb. 28, 1995) discloses an actuating element for a switch, whichactuating element is connected via a hinge to a partition associatedwith a housing wall. The housing wall has no guides for the partition.

Furthermore, an electrical pushbutton switch with an actuating element,pivotably supported on a housing, for applying pressure to a switchingcontact is known from EP 0 887 819 A2. A pushbutton support is providedfor the pivotable support of each actuating element, said supportconsisting of at least one support bracket, with support pins, fixed tothe housing, and of a corresponding flange hole located in a side wallof the actuating element.

The invention addresses the problem of creating an actuating element ofthe type initially cited that has a small number of individual parts, ismechanically robust, and in addition, is simple and economical toproduce and mount.

The invention solves this problem in that a film hinge is provided asthe hinge, said film hinge connecting the actuating element to apartition engaged with the housing, said partition covering theassociated housing wall of the outside and being guided on the latter,and in that at least one stop arm is formed on the underside of theactuating element, said arm extending behind a projection formed on thehousing wall opposite the film hinge.

As a consequence of this measure, it is not necessary to provideadditional structural components for pivotable support of the actuatingelement. As a consequence of connecting the actuating element to thepartition, it is possible to manufacture this partition from a suitableplastic upon which mechanical demands can be placed that differ incomparison to the material of the housing. For example, a plasticreinforced with glass fibers with high strength is used to manufacturethe housing, said plastic not being usable in a film hinge and thevisible surface of the actuating element. The actuating element isproduced, with the film hinge and the relatively lightly loadedpartition, from a non-reinforced plastic that assures the necessaryelasticity and a high surface quality necessary for the visible surfacesof the actuating element. Relatively rapid assembly is assured in thatthe partition can be engaged with the housing. When the partition isarranged paralled to a housing wall, an increased stability of thehousing is achieved. Furthermore, connection to a housing ofdifferently-formed actuating elements is possible after an appropriatechange of the die mole, so that given a design change, only theactuating elements are adapted while the housing and the switch partsinserted in it are kept the same. As a consequence of the guidance ofthe partition on the associated housing wall, positional fixationbetween the housing and the actuating element is assured. In order toprevent the actuating element from pivoting counter to the direction inwhich it is pressed, at least one stop arm is formed on the underside ofthe actuating element, said arm extending behind a projection formed onthe housing wall opposite the film hinge

The guide is advantageously designed as a dovetail guide. The dovetailguide assures guidance in two axes, and accordingly provides precisepositioning of the actuating element in relation of the housing.

Several spaced-apart guide ridges of the housing wall, and correspondingguide grooves in the partition, are preferably provided. The guideridges extend over approximately the entire height of the housing wall,and the guide grooves extend over approximately the entire height of thepartition. Rotation of the partition relative to the housing wall ispractically excluded by the relatively great lengths of the guides andtheir spacing apart from each other.

According to an advantageous further development of the concept of theinvention several actuating elements are arranged parallel to each otherperpendicularly to the longitudinal axis of the housing, those actuatingelements each being connected to the partition via at least one filmhinge. As a result, several switching functions are integrated into onehousing; of course, a separate switching contact to be pressed isassociated with each of the actuating elements.

Since the film hinge on the visible side of the actuating element isconsidered objectionable on visual and tactile grounds, the partitionextends into the film hinge and an actuating surface of the actuatingelement extends substantially perpendicularly from the partition and/orthe film hinge. The film hinge is thereby associated with the outermostedge area of the actuating element.

The one end face of the actuating element is preferably aligned flushwith the partition and the associated film hinge, and the other end facepreferably extends over part of the housing wall opposite the partition.Thus, the entire housing surface and the film hinges are covered by theactuating element or elements.

In order to effectively prevent the partition with the actuating elementfrom being pulled off of the housing, at least one clip arm with a clipopening for latching reception of a clip projection formed on thehousing wall is advantageously designed in the partition.

According to a further embodiment, perforated projections for attachmentbetween spokes of a steering wheel are provided on a base of thehousing, said base holding the switching contacts designed as amicroswitch. The entire switch, which can be used, e.g., to control aTempomat, is reliably connected to the steering wheel via the holes byscrews.

In order to adapt the geometry of the housing to the installationsituation on a steering wheel, the cross section of the housing isadvantageously designed in a substantially triangular shape, in whichthe housing walls of the longitudinal sides form the sides of thetriangle, an end face housing wall forms the base, and the other endface housing wall essentially forms an arcuate connection of thelongitudinal-side housing walls.

The free end faces of the actuating elements opposite the film hingesare advantageously designed in an arc. In this manner, even theactuating elements are adapted to the contour of the steering wheel.

The switching contacts are relatively sensitive components that must beprotected from being overloaded by too great a force when the actuatingelements are pressed. Therefore, a stop is advantageously associatedwith each actuating element on the side opposite the film hinge, saidstop coming to rest against the end face of the corresponding housingwall upon being pressed.

In order to convert the pivoting movement of the actuating element intoa straight-line movement for applying pressure to the microswitchassociated with it, a push rod associated with each actuating elementfor applying pressure to the corresponding microswitch is movablyarranged, preferably on one of the housing walls of the longitudinalsides.

Of course, the previously cited features still to be explained in thefollowing can be used not only in the particular combination indicated,but also in other combinations without departing from the scope of thepresent invention.

The invention is explained in the following using an exemplaryembodiment and making reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an oblique view of a switch arrangement with actuatingelements in accordance with the invention.

FIG. 2 shows an oblique view of a detail II according to FIG. 1.

FIG. 3 shows another oblique view of detail II according to FIG. 1.

FIG. 4 shows a partially exploded view of detail II according to FIG. 1.

FIG. 5 shows an exploded view of detail II according to FIG. 1.

FIG. 6 shows a view of detail VI according to FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The switch arrangement serves to control a cruise control device, aso-called Tempomat, of a motor vehicle, and comprises two electricalswitches 1, each with a housing 2. Switches 1 are connected to oneanother via leads 3 that end in common plug contacts 4 for connection tothe vehicle electrical system. Two individual switches 5 are housed inthe one housing 2, of which one serves to cut in the cruise controldevice and the other to cut it out. The other housing 2 receives threeindividual switches 5, one of which is provided for resetting the setspeed, one for storing the instantaneous speed and increasing it and onefor reducing the instantaneous speed of the motor vehicle, by means ofthe cruise control device. Switches 1 are fastened directly to asteering wheel (not shown) between its spokes so that the driver doesnot have to remove his hands from the steering wheel when pressingindividual switches 5.

Each individual switch 5 comprises a pivotably supported actuatingelement 6 connected via spaced-apart film hinges 7 to partition 8, whichpartition 8 also supports the other actuating elements 6 associated withswitch 1 via separate and spaced-apart film hinges 7. Partition 8extends into film hinges 7 and actuating surface 11 of actuating element6, this surface being provided with symbols 9 and tactilely perceivableelevations 10 and running substantially perpendicularly to partition 8.In order to cover partition 8 and also film hinges 7 such that they arenot noticeable in the installed state of switches 1, the one end face 12of actuating element 6 is aligned flush with partition 8, and thuscovers partition 8 and film hinges 7 with actuating surface 11. End face13 of actuating element 6, which is opposite to partition 8, extendspartially over corresponding housing wall 14. Since actuating elements6, which are arranged parallel to each other, extend for their entirewidth over the entire upper side of housing 2, the housing is barelynoticeable visually in a top view of the switch.

Partition 8 extends parallel to longitudinal-side housing wall 15 and islodged on it by means of spaced-apart dovetail guides 16. Guide ridges17 are formed on housing wall 15 and guide grooves 18 corresponding tothem are let into partition 8, said guide ridges 17 extending overapproximately the entire height of housing wall 15 and said guidegrooves extending over approximately the entire height of partition 8.In order to effectively secure partition 8 with associated actuatingelements 8 to housing 2, clip arm 19 with clip opening 20 is formed inpartition 8 into which opening a corresponding clip projection 21 ofhousing wall 15 engages.

In order to achieve a harmonious integration of switch 1 with thesteering wheel, the cross-sectional area of housing 2 is designedsubstantially triangularly, with longitudinal-side housing walls 14, 15forming the sides of the triangle, end-face housing wall 22 the base,and the other end-face housing wall 23 substantially forming an arcuateconnection between longitudinal-side housing walls 14, 15. Fastening ofswitch 1 is effected via perforated projections 24 formed in housing 2which receive a snapped-in socket 25. Metallic threaded sleeves 26 areinserted into holes 24.

Base 25 carries guide plate 27 with switching contacts 29 designed asmicroswitches 28, a separate microswitch 28 being associated with eachindividual switch 5. Push rod 30 is provided for actuating microswitch28. Push rod 30 comprises receptacle 31 partially surroundingmicroswitch 28, which receptacle is connected to guide surface 32running perpendicularly to it. Guide surface 32 is movably guided insubstantially T-shaped groove 33, which groove 33 receives pressurespring 34 at the same time, said spring being supported betweenunderside 35 of guide surface 32 and the bottom of groove 33.Projections 35 are formed on housing wall 14 on both sides of groove 33and corresponding stop arms 36 extend behind these projections. The stoparms 36 are formed on the bottom of actuating element 6.

When actuating element 6 is pressed, it pivots on associated film hinge7 and pushes push rod 30 against the force of pressure spring 34 ingroove 33 in the direction of microswitch 28. An actuating element stop(not shown) comes to rest against the housing in a pressed end positionof actuating element 6, whereby microswitch 28 is protected frommechanical overloading, and receptacle 31 of push rod 30 actuatesmicroswitch 28. After actuating element 6 is released, it pivots backinto an un-pressed end position as a result of the force of pressurespring 34 acting on push rod 30, and the stop arms of actuating element6 come to rest against associated projections 35 of housing wall 14.

What is claimed is:
 1. An actuating element for an electrical switch,comprising: an actuating body, at least one switching contact influencedby said actuating body, wherein said switching contact is mounted inswitch housing by way of a pivot mechanism, wherein said pivot mechanismincludes a film hinge connecting the actuating body to a partitionengaged with the switch housing wherein said partition covers anassociated housing wall at least one stop arm formed on an underside ofthe actuating body, said arm extending behind a projection formed on ahousing wall opposite the film hinge.
 2. The actuating element accordingto claim 1, wherein said partition is guided on the housing wall by wayof the guide is designed as a dovetail guide.
 3. The actuating elementaccording to claim 1, further including several spaced-apart guide websof die housing wall, and corresponding guide grooves in the partition,said guide webs extending over approximately an entire height of thehousing wall, and said guide grooves extending over approximately anentire height of the partition.
 4. The actuating element according toclaim 1, wherein several actuating bodies are arranged parallel to eachother perpendicular to a longitudinal axis of the switch housing, saidactuating bodies each being connected to the partition by way of atleast one film hinge.
 5. The actuating element according to claim 1,wherein the partition extends into the film hinge, and wherein anactuating surface of the actuating body runs substantiallyperpendicularly from the partition or the film hinge.
 6. The actuatingelement according to claim 5, wherein a first end face of the actuatingbody is aligned flush with the partition and the associated film hinge,and wherein a second end face of the actuating body extends over part ofthe housing wall opposite the partition.
 7. The actuating elementaccording to claim 1, wherein at least one clip arm, with a clip openingfor latching reception of a clip projection formed on the housing wall,is formed in the partition.
 8. The actuating element according to claim1, further including perforated projections, for attachment betweenspokes of a steering wheel, connected on a base of the housing, whereinsaid base holds the switching contacts designed as a microswitch.
 9. Theactuating element according to claim 8, wherein at least one stop inassociated with each actuating body on the side opposite to the filmhinge, said stop coming to rest on an end face of the correspondinghousing wall when pressure is applied.
 10. The actuating elementaccording to claim 1, wherein a cross section of the housing issubstantially triangular in shape, the housing wall forms the sides ofthe triangle, and wherein an end-face housing wail forms the base, andthe other end-face housing wall essentially forms an arcuate connectionof the longitudinal-side housing walls.
 11. The actuating elementaccording to claim 10, wherein the actuating bodies are designed in anarc.
 12. The actuating element according to claim 1, further including apush rod, associated with each actuating body for applying pressure tothe corresponding microswitch is movably arranged on one of the housingwalls (14, 15) of the longitudinal sides.